1. Field of the Invention
The invention relates to articles of manufacture. In particular, a coaxial cable connector includes a moving nose urged from an opening at an end of the connector.
2. Discussion of the Related Art
In cable television and satellite television systems (“CATV”), signal management includes maintaining circuit continuity and reducing unwanted radio frequency (“RF”) signals exchanged at coaxial cable connectors. Among other things, signal management therefore aims to improve signal transmission, to improve signal to noise ratio, and to avoid distortion associated with saturated reverse amplifiers and related optic transmission equipment.
Past efforts to limit interfering RF signals into CATV systems have been reported, including the efforts of this inventor. Solutions have included increased use of traditional connector shielding, multi-braid coaxial cables, connection tightening guidelines, increased use of traditional splitter case shielding, and high pass filters limiting low frequency spectrum signal ingress and interference with active home CATV systems.
While it appears the industry accepts the status quo as satisfactory, there remain, in the inventor's view, good reasons to develop improvements that further improve the shielding of coaxial cable connectors and in particular female F-Type connectors (“F” connectors).
In the inventor's view, all of poor signal transport through mated connectors, stray signal ingress into mated or open connectors, and signal emission from mated or open connectors represent potential problems.
Stray RF signals can cause problems in CATV systems such as home CATV systems. For example, when a subscriber leaves a CATV connection such as a wall-mounted connector or coaxial cable drop connector disconnected/open, an unprotected stray signal ingress point is created. The open connector end exposes a normally metallically enclosed and shielded signal conductor and can be a significant source of unwanted RF ingress alone, or in the aggregate with other signal ingress locations.
F connectors are commonly used in the United States for interconnecting cable and satellite television equipment in the home. Wall mounted female F connectors and/or coaxial cable “drop(s)” including a male F connector commonly supply a signal to the TV set, cable set-top box, or internet modem. Notably, wall mounted female F connectors are commonly connected via a coaxial cable terminated with male connectors at opposite ends.
Whether a CATV signal is supplied to equipment via a drop cable or via a wall mounted connector, this connection is a potential source of unwanted RF signal ingress. Wall mounted connectors left open or coaxial cables attached to the wall mounted connector but otherwise open are points of unwanted RF signal transfers. Similarly, drop cables such as those terminated with a male F connector become unwanted RF signal transfer points when left open.
Multiple CATV connections in a home increase the likelihood that some connections will be left open and/or unprotected, making them, for example, a potential source of unwanted RF ingress. And, when subscribers move out of a home, CATV connections are typically left open, another situation that creates undesirable RF signal transfer points with the CATV distribution system.
A known method capable of eliminating unwanted RF ingress in a CATV system involves the use of metal end caps to cover unused F connectors in the home or, to place a single metal cap over the feeder F connection at the home network box. But, in the usual case home CATV connections are left active and open, an undesirable but accepted practice the industry tolerates to avoid expensive service calls associated with new tenants and/or providing the CATV signal in additional rooms.
The inventor's experience shows current solutions for reducing unwanted RF ingress resulting from open connectors are not successful and/or are not widely used. Therefore, to the extent the CATV industry recognizes a need to further limit interfering RF ingress into CATV systems, it is desirable to have connectors that reduce unwanted RF signal transfers when connections coupled to the CATV system are left open.
Points of unwanted RF signal transfer are created by loosely mated connectors. In particular, loose connectors typically have gaps in the electromagnetic containment intended to enclose signal conductors and to prevent unwanted signal ingress. These gaps also interrupt ground path circuits. Here, ingressing signals travel in gaps between connector parts such as a gap between the nut and mandrel flange resulting from a loose fitting nut. Notably, in some recent male F connectors this problem is resolved or mitigated using a supplemental spring contact to either electrically interconnect open electrical contacts or provide an axial spring force to push the nut against the connector mandrel flange. (See, for example, U.S. Pat. Nos. 6,712,631, 6,716,062, and 7,753,705.) Some others utilize a spring located behind the male connector nut. One solution (i.e. U.S. Pat. No. 6,712,631) uses a split washer as a spring to mitigate the problem.
Notably, while the signal ingress problem has received some attention in the cable television industry, prior art solutions have relied on modifications made to the male F connector, not modifications made to the female F connector. Further, known solutions do not mitigate the problem of undesirable RF signal transfers via loose nut threads.
The present inventor knows of no F connector ingress reduction solutions teaching and relying on modifications of the female connector. And, while moving part activators have uses in shunt switches and clamps, these devices are unlike embodiments of the present invention.
Known signal ingress solutions also do not generally teach urging 360 degree contact between a nut rim and mandrel flange to create an RF barrier. In particular, references using moving parts were designed and used for purposes other than meeting the RF shielding needs of present-day CATV service providers.
Some references use moving insulators. However, these references differ from the present invention because they fix the connector center conductor to an activation mechanism. For example, U.S. Pat. Nos. 4,660,921 and 5,598,132 use a moving center pin attached a moving insulator. Among other things, this design is not applicable to device mounted connectors and is unreliable because of uncertain contact with a center conductor. Notably, installers hand-craft coaxial cable center conductor lengths and, where too short, these lengths fail to contact the moving center pin.
U.S. Pat. No. 6,270,367 requires a center conductor coiled into a spring and acting as a series inductor. As skilled artisans will appreciate, such structures are generally ill suited to high frequency operations including frequencies over 20 MHz, a limitation far short of present day gigahertz requirements.
U.S. Pat. No. 6,329,251 discloses the center conductor of the connector as an operational component in transferring forces. Such a design compromises the connector conductive center pin and compromises RF performance due to the larger size center pin required.
U.S. Pat. No. 7,938,680 (the “'680” patent) includes a continuity spring forward of the front ferrule face with its contact point facing radially inward against the female body but enclosed in a tube extended from the forward part of the ferrule post. In the '680 patent, the approach to resolving the electrical continuity problem while avoiding the disadvantage of other spring loaded designs is to extend a sleeve attached to the post forward end where an inward connection spring is located. This would electrically connect the spring to the tube via contact with the outer sleeve. But, this approach also has disadvantages. For example, there is a need for an expensive, very large outer nut to contain the new internal sleeve. In addition, the F connector tightening tools and industry specifications generally require a standard hex nut with an 11 mm hex-hex dimension, requirements that are not possible with this inner sleeve design.
Each of U.S. Pat. Nos. 7,938,680, 6,712,631, 6,716,062, 7,753,705, 4,660,921, 5,598,132, 6,270,367, and 6,329,251 is incorporated herein by reference in its entirety and for all purposes.
The interface between male and female coaxial connectors requires good contact of the outer shield in order to both transport the RF signals with integrity and to prevent unwanted signal ingress. These goals are served in a variety of ways with RF coaxial connectors. One method used on BNC connectors is to spring load the grounding components on male and female connectors. Another method uses threaded male female interfaces and precise tightening specifications to set torque levels insuring proper operation. Industry experience shows maintenance of required RF performance using this method requires both a high level of installation craft sensitivity as well as suitable environmental conditions such as environments free of vibration and excessive temperature changes. But, F type coaxial connectors are used in consumer applications where there is no assurance the user will follow difficult or even any particular installation specifications. Therefore a need exists for F connectors that insure proper electrical continuity despite a loosened male connector nut.
Male F type coaxial connectors typically use an internally threaded nut to connect the male connector with a female connector having corresponding external threads. In various examples, tightly mated connectors maintain a good connection from the coaxial cable outer ground/shield and a male connector ferrule tube/post to the female connector outer body. But, if the male nut is not fully tightened to the female connector, the ground connection between the cable and a connected device/cable may be faulty. Known methods remedying the loose connector nut problem frequently include a spring behind a male connector mandrel flange to spring the flange against the female connector end-face. Solutions of this sort suffer a disadvantage when the cable is off-axis due to a loose nut since the expected parallel interface planes which compromises conductivity.